Flip-flop including 3-state inverter

ABSTRACT

A flip-flop includes an input interface, a first latch, a third inverter, and a second latch. The third inverter and the fifth inverter include first transistors of a first type formed between a first power contact and a second power contact supplied with a power supply voltage on first-type fins, and second transistors of a second type formed between a first ground contact and a second ground contact supplied with a ground voltage on second-type fins.

CROSS-REFERENCE TO THE RELATED APPLICATIONS

A claim for priority under 35 U.S.C. § 119 is made to Korean PatentApplication Nos. 10-2016-0089380 filed Jul. 14, 2016 and 10-2017-0064763filed May 25, 2017, in the Korean Intellectual Property Office, thedisclosures of which are incorporated herein in their entirety byreference.

BACKGROUND

Apparatuses consistent with example embodiments of the inventive conceptdescribed herein relate to a semiconductor circuit, and moreparticularly, relate to a flip-flop including an inverter.

A flip-flop is a semiconductor element that is universally used invarious semiconductor circuits. A size of the flip-flop may decrease asa semiconductor process is miniaturized. Semiconductor circuits aremanufactured with a Fin Field Effect Transistor (Fin-FET) structure as aFin-FET-based semiconductor process develops. Accordingly, the flip-flopis also manufactured by using the Fin-FET-based semiconductor process.In a case where the flip-flop is manufactured by using the Fin-FET-basedsemiconductor process, a design is limited due to an inherent processcharacteristic of the Fin-FET, thereby causing deterioration in aflip-flop characteristic and a decrease in yield.

SUMMARY

Example embodiments of the inventive concept provide a Fin-FET-basedflip-flop capable of preventing deterioration in a characteristic and adecrease in yield. Also, example embodiments of the inventive conceptprovide a flip-flop having improved efficiency in layout.

According to an aspect of an example embodiment, there is provided aflip-flop which may include: an input interface that receives a firstsignal and outputs the received first signal as a second signal insynchronization with a clock; a first latch that includes a firstinverter and a second inverter and stores the second signal output fromthe input interface in synchronization with the clock; a third inverterthat outputs the second signal stored in the first latch as a thirdsignal in synchronization with the clock; and a second latch thatincludes a fourth inverter and a fifth inverter and stores the thirdsignal output from the third inverter in synchronization with the clock.The third inverter and the fifth inverter may include first transistorsof a first type formed between a first power contact and a second powercontact supplied with a power supply voltage on first-type fins, andsecond transistors of a second type formed between a first groundcontact and a second ground contact supplied with a ground voltage onsecond-type fins.

According to an aspect of an example embodiment, the flip-flop which mayinclude: an input interface that receives a first signal and outputs thereceived first signal as a second signal in synchronization with aclock; a first latch that includes a first inverter and a secondinverter and stores the second signal output from the input unit insynchronization with the clock; a third inverter that outputs the secondsignal stored in the first latch as a third signal in synchronizationwith the clock; a second latch that includes a fourth inverter and afifth inverter and stores the third signal output from the thirdinverter in synchronization with the clock, and a sixth inverter thatinverts the third signal and outputs the inverter signal as a fourthsignal. The third inverter may include first and second P-typemetal-oxide-semiconductor (PMOS) transistors and first and second N-typemetal-oxide-semiconductor (NMOS) transistors. The fifth inverter mayinclude third and fourth PMOS transistors and third and fourth NMOStransistors. The first to fourth PMOS transistors may be disposedbetween a first power contact and a second power contact supplied with apower supply voltage on first-type fins, and the first to fourth NMOStransistors may be disposed between a first ground contact and a secondground contact supplied with a ground voltage on second-type fins.

According to an aspect of an example embodiment, there is provided aflip-flop which may include: a master latch which includes at least oneinverter and is configured to receive an input signal from an inputinterface; a slave latch which includes at least one inverter includinga feedback loop transistor inverter; and a 3-state inverter disposedbetween the master latch and the slave latch to receive an output signalof the master latch and drive the slave latch with an output signal ofthe feedback loop transistor inverter. The inverter of the master latch,the feedback loop transistor inverter, and the 3-state inverter may havea same structure of transistors, and controlled by a clock signal and aninverter clock signal which are respectively input to gates of twodifferent-type transistors.

BRIEF DESCRIPTION OF THE FIGURES

The above and other objects and features will become apparent from thefollowing description with reference to the accompanying drawings,wherein like reference numerals refer to like parts throughout thevarious figures unless otherwise specified, and wherein:

FIG. 1 is a circuit diagram illustrating a flip-flop according to anexample embodiment of the inventive concept;

FIG. 2 illustrates an example of a clock generator that supplies firstand second clock signals to the flip-flop of FIG. 1;

FIG. 3 illustrates an example of a layout in which a third inverter anda fifth inverter are implemented with a Fin-FET structure;

FIG. 4 illustrates an example in which a fourth inverter shares a powersupply voltage and a ground voltage of the third and fifth inverters ofFIG. 3;

FIG. 5 illustrates an application example of arrangement of the thirdand fifth inverters;

FIG. 6 illustrates an example in which the power supply voltage and theground voltage of the third and fifth inverters of FIG. 5 are shared;

FIG. 7 illustrates an application example of the third and fifthinverters of FIG. 5;

FIG. 8 illustrates an example in which the power supply voltage and theground voltage of the third and fifth inverters of FIG. 7 are shared;

FIG. 9 illustrates an application example of the flip-flop of FIG. 1;

FIG. 10 illustrates an application example of the flip-flop of FIG. 9;

FIG. 11 illustrates an example in which the fourth inverter of FIG. 10shares the power supply voltage and the ground voltage with the thirdand fifth inverters;

FIG. 12 illustrates an application example of arrangement of the thirdto fifth inverters of FIG. 11;

FIG. 13 illustrates another application example of arrangement of thethird to fifth inverters of FIG. 11;

FIG. 14 illustrates another application example of the flip-flop of FIG.9;

FIG. 15 illustrates an example in which the fourth inverter of FIG. 14shares the power supply voltage and the ground voltage with the thirdand fifth inverters;

FIG. 16 illustrates an application example of arrangement of the thirdto fifth inverters of FIG. 15; and

FIG. 17 illustrates another application example of arrangement of thethird to fifth inverters of FIG. 15.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

Below, example embodiments of the inventive concept will be describedclearly and in detail with reference to accompanying drawings to such anextent that an ordinarily skilled one in the art implements the exampleembodiments.

FIG. 1 is a circuit diagram illustrating a flip-flop 100 according to anexample embodiment of the inventive concept. Referring to FIG. 1, theflip-flop 100 includes an input interface 110, a first inverter 130, asecond inverter 140, a third inverter 150, a fourth inverter 160, afifth inverter 170, and a sixth inverter 180.

The input interface 110 includes first to tenth transistors 111 to 120.The first and second input transistors 111 and 112 are connected inseries between a power node, to which a power supply voltage VDD issupplied, and the fifth transistor 115. The first and second inputtransistors 111 and 112 may be P-type transistors. An input signal D maybe transferred to a gate of the first input transistor 111, and a scanenable signal SE may be transferred to a gate of the second inputtransistor 112.

The third and fourth input transistors 113 and 114 are connected inseries between the power node and the fifth input transistor 115. Thethird and fourth input transistors 113 and 114 may be connected inparallel with the first and second input transistors 111 and 112 betweenthe fifth input transistor 115 and the power node. The third and fourthinput transistors 113 and 114 may be P-type transistors. A scan inputsignal SI may be transferred to a gate of the third input transistor113, and a scan enable bar signal SE may be transferred to a gate of thefourth input transistor 114.

The fifth and sixth input transistors 115 and 116 are connected inseries between the second and fourth input transistors 112 and 114 andthe seventh and ninth input transistors 117 and 119. The fifth inputtransistor 115 may be a P-type transistor. The sixth input transistor116 may be an N-type transistor. A second clock signal b may betransferred to a gate of the fifth input transistor 115, and a firstclock signal n may be transferred to a gate of the sixth inputtransistor 116.

The seventh and eighth input transistors 117 and 118 are connected inseries between a ground node, to which a ground voltage VSS is supplied,and the sixth input transistor 116. The seventh and eighth inputtransistors 117 and 118 may be N-type transistors. The scan enable barsignal SE may be transferred to a gate of the seventh input transistor117, and the input signal D may be transferred to a gate of the eighthinput transistor 118.

The ninth and tenth input transistors 119 and 120 are connected inseries between the ground node and the sixth input transistor 116. Theninth and tenth input transistors 119 and 120 may be connected inparallel with the seventh and eighth input transistors 117 and 118between the sixth input transistor 116 and the ground node. The ninthand tenth input transistors 119 and 120 may be N-type transistors. Thescan enable signal SE may be transferred to a gate of the ninth inputtransistor 119, and the scan input signal SI may be transferred to agate of the tenth input transistor 120.

A node between the fifth and sixth input transistors 115 and 116 may bean output of the input interface 110. The output of the input interface110 is connected to an input of the first inverter 130 and an output ofthe second inverter 140.

The input interface 110 may operate in a first mode and a second mode.In the first mode, the scan enable signal SE may be deactivated. Forexample, the scan enable signal SE may have the ground voltage VSS or avoltage lower than the ground voltage VSS. In this case, the second andseventh input transistors 112 and 117 are turned on, and the fourth andninth input transistors 114 and 119 are turned off. The input interface110 may block the scan input signal SI, and may output the input signalD (or an inverted version of the input signal D) to the first inverter130 in synchronization with the first and second clock signals n and b.

In the second mode, the scan enable signal SE may be activated. Forexample, the scan enable signal SE may have the power supply voltage VDDor a voltage similar to the power supply voltage VDD. In this case, thesecond and seventh input transistors 112 and 117 are turned off, and thefourth and ninth input transistors 114 and 119 are turned on. The inputinterface 110 may block the input signal D, and may output the scaninput signal SI (or an inverted version of the scan input signal SI) tothe first inverter 130 in synchronization with the first and secondclock signals n and b.

In an example embodiment, the scan input signal SI may be used for aspecial purpose such as a scan test. The input signal D may be used foran original design purpose of a semiconductor circuit including theflip-flop 100.

The first inverter 130 inverts an output signal of the input interface110, and transfers the inverted output signal to the second inverter 140and the third inverter 150. The first inverter 130 includes a 1_1thtransistor 131 and a 1_2nd transistor 132. The 1_1st and 1_2nd inputtransistors 131 and 132 are connected in series between the power nodeand the ground node. Gates of the 1_1st and 1_2nd input transistors 131and 132 are connected to the output of the input interface 110 and theoutput of the second inverter 140. A node between the 1_1st and 1_2ndinput transistors 131 and 132 may be the output of the first inverter130. The output of the first inverter 130 is connected to inputs of thesecond inverter 140 and the third inverter 150.

The second inverter 140 inverts an output signal of the first inverter130 and transfers the inverted output signal to the first inverter 130.The second inverter 140 includes 2_1st to 2_4th transistors 141 to 144.The 2_1st to 2_4th transistors 141 to 144 are connected in seriesbetween the power node and the ground node. The output signal of thefirst inverter 130 is transferred to gates of the 2_1st and 2_4thtransistors 141 and 144. The first clock signal n is transferred to agate of the 2_2nd transistor 142. The second clock signal b istransferred to a gate of the 2_3rd transistor 143. The second inverter140 may be a 3-state inverter that operates in synchronization with thefirst and second clock signals n and b. A node between the 2_2nd and2_3rd transistors 142 and 143 may be the output of the second inverter140. The output of the second inverter 140 is connected to the input ofthe first inverter 130.

The first and second inverters 130 and 140 may constitute a master latchof the flip-flop 100.

The third inverter 150 inverts the output signal of the first inverter130, and transfers the inverted output signal to the fourth inverter160. The third inverter 150 includes 3_1st to 3_4th transistors 151 to154. The 3_1st to 3_4th transistors 151 to 154 are connected in seriesbetween the power node and the ground node. The output signal of thefirst inverter 130 is transferred to gates of the 3_1st and 3_4thtransistors 151 and 154. The first clock signal n is transferred to agate of the 3_2nd transistor 152. The second clock signal b istransferred to a gate of the 3_3rd transistor 153. The third inverter150 may be a 3-state inverter that operates in synchronization with thefirst and second clock signals n and b. A node between the 3_2nd and3_3rd transistors 152 and 153 may be an output of the third inverter150. The output of the third inverter 150 is connected to an input ofthe fourth inverter 160.

The fourth inverter 160 inverts an output signal of the third inverter150, and transfers the inverted output signal to the fifth inverter 170.The fourth inverter 160 includes a 4_1th transistor 161 and a 4_2ndtransistor 162. The 4_1st and 4_2nd input transistors 161 and 162 areconnected in series between the power node and the ground node. Gates ofthe 4_1st and 4_2nd input transistors 161 and 162 are connected to theoutput of the third inverter 150 and an output of the fifth inverter170. A node between the 4_1st and 4_2nd input transistors 161 and 162may be the output of the fourth inverter 160. The output of the fourthinverter 160 is connected to inputs of the fifth inverter 170.

The fifth inverter 170 inverts an output signal of the fourth inverter160, and transfers the inverted output signal to the fourth inverter160. The fifth inverter 170 includes 5_1st to 5_4th transistors 171 to174. The 5_1st to 4_4th transistors 171 to 174 are connected in seriesbetween the power node and the ground node. The output signal of thefourth inverter 160 is transferred to gates of the 5_1st and 5_4thtransistors 171 and 174. The second clock signal b is transferred to agate of the 5_2nd transistor 172. The first clock signal n istransferred to a gate of the 5_3rd transistor 173. The fifth inverter170 may be a 3-state inverter that operates in synchronization with thefirst and second clock signals n and b. A node between the 5_2nd and5_3rd input transistors 172 and 173 may be an output of the fifthinverter 170. The output of the fifth inverter 170 is connected to theinput of the fourth inverter 160.

The fourth and fifth inverters 160 and 170 may constitute a slave latchof the flip-flop 100.

The sixth inverter 180 inverts the output signal of the third inverter150, and transfers the inverted output signal as an output signal q. Thesixth inverter 180 includes a 6_1th transistor 181 and a 6_2ndtransistor 182. The 6_1st and 6_2nd transistors 181 and 182 areconnected in series between the power node and the ground node. Gates ofthe 6_1st and 6_2nd transistors 181 and 182 are connected to the outputof the third inverter 150 and the output of the fifth inverter 170. Anode between the 6_1st and 6_2nd transistors 181 and 182 may be theoutput of the sixth inverter 180.

According to an example embodiment of the inventive concept, a signaltransfer between the master latch including the first and secondinverters 130 and 140 and the slave latch including the fourth and fifthinverters 160 and 170 is performed by the third inverter 150.

In general, to reduce the number of transistors, a signal transferbetween a master latch and a slave latch of a flip-flop is performed bya transmission gate that operates in synchronization with clock signals.In this case, to prevent an error (i.e., a back flow of a signal) that asignal of the master latch is changed by a signal of the slave latch,there is used a sizing technology for making the sizes of the 1_1st and1_2nd transistors 131 and 132 of the first invert 130 of the masterlatch larger than the sizes of the 5_1st to 5_4th of the fifth inverter170 of the slave latch. However, the sizing technology in the Fin-FETprocess makes the number of fins used in transistors different from eachother, thereby causing a taper. The taper causes deterioration in aflip-flop characteristic and a decrease in yield.

To prevent the above-described issues, the flip-flop 100 according to anexample embodiment of the inventive concept uses the third inverter 150for a signal transfer between the master latch and the slave latch.Accordingly, a back flow of a signal is prevented. Also, since there isno need to use the sizing technology, it is possible to preventoccurrence of the taper.

The flip-flop 100 according to an example embodiment of the inventiveconcept provides a layout that allows improvement of layout efficiencyof the flip-flop 100 including the third inverter 150. Accordingly, eventhough the number of transistors increases due to the third inverter150, the overall size of the flip-flop 100 is prevented from increasing.

FIG. 2 illustrates an example of a clock generator 190 that supplies thefirst and second clock signals n and b to the flip-flop 100 of FIG. 1.Referring to FIG. 2, the clock generator 190 includes first to fourthtransistors 191 to 194. The first and second transistors 191 and 192 areconnected in series between the power node and the ground node. Thethird and fourth transistors 193 and 194 are connected in series betweenthe power node and the ground node. The first and third transistors 191and 193 may be P-type transistors, and the second and fourth transistors192 and 194 may be N-type transistors.

The first and second transistors 191 and 192 may constitute an inverter.The first and second inverts 191 and 192 may invert a clock signal CLKto output the first clock signal n. The clock signal CLK may be a clocksignal used in a semiconductor circuit including the flip-flop 100. Thethird and fourth transistors 193 and 194 may constitute an inverter. Thethird and fourth inverts 193 and 194 may invert the first clock signal nto output the second clock signal b.

FIG. 3 illustrates an example of a layout in which the third inverter150 and the fifth inverter 170 are implemented with a Fin-FET structure.Referring to FIGS. 1 and 3, the third and fifth inverters 150 and 170may be formed in first to fourth fins FIN1 to FIN4. The first to fourthfins FIN1 to FIN4 may be disposed in parallel with one another. Thefirst and second fins FIN1 and FIN2 may form a first active area R1 of aP-type. The third and fourth fins FIN3 and FIN4 may form a second activearea R2 of an N-type.

First to sixth gate patters GP1 to GP6 may be disposed on the first tofourth fins FIN1 to FIN4. The first to sixth gate patterns GP1 to GP6may be disposed in parallel with one another. The first to sixth gatepatters GP1 to GP6 may be disposed perpendicular to the first to fourthfins FIN1 to FIN4.

A first power contact PC1 may be provided between the first and secondgate patterns GP1 and GP2 in the first active area R1. A second powercontact PC2 may be provided between the fifth and sixth gate patternsGP5 and GP6 in the first active area R1. The first and second powercontacts PC1 and PC2 may extend in a direction perpendicular to thefirst active area R1, and may be connected with a wiring over the firstand second active areas R1 and R2. The first power contact PC1 maysupply the power supply voltage VDD to a node (e.g., a source or adrain) of the 3_1st transistor 151. The second power contact PC2 maysupply the power supply voltage VDD to a node (e.g., a source or adrain) of the 5_1st transistor 171.

A first ground contact GC1 may be provided between the first and secondgate patterns GP1 and GP2 in the second active area R2. A second groundcontact GC2 may be provided between the fifth and sixth gate patternsGP5 and GP6 in the second active area R2. The first and second groundcontacts GC1 and GC2 may extend in a direction perpendicular to thesecond active area R2, and may be connected with a wiring over the firstand second active areas R1 and R2. The first ground contact GC1 maysupply the ground voltage VSS to a node (e.g., a source or a drain) ofthe 3_4th transistor 154. The second ground contact GC2 may supply theground voltage VSS to a node (e.g., a source or a drain) of the 5_4thtransistor 174.

In the first active area R1, the second gate pattern GP2 may form the3_1st transistor 151 together with portions of the first active area R1which are adjacent to the second gate pattern GP2. In the first activearea R1, the third gate pattern GP3 may form the 3_2nd transistor 152together with portions of the first active area R1 which are adjacent tothe third gate pattern GP3. The 3_1st and 3_2nd transistors 151 and 152may be connected in series to each other.

In the second active area R2, the second gate pattern GP2 may form the3_4th transistor 154 together with portions of the second active area R2which are adjacent to the second gate pattern GP2. In the second activearea R2, the third gate pattern GP3 may form the 3_3rd transistor 153together with portions of the second active area R2 which are adjacentto the third gate pattern GP3. The 3_3rd and 3_4th transistors 153 and154 may be connected in series to each other.

A first contact C1 may be provided in the second gate pattern GP2 of the3_1st and 3_4th transistors 151 and 154. The first contact C1 may extendin a direction perpendicular to the first and second active areas R1 andR2, and may be connected with a wiring over the first and second activeareas R1 and R2. The first contact C1 may be electrically connected withan output of the first inverter 130 and an input of the second inverter140.

The third gate pattern GP3 may be divided into a first portioncorresponding to the first active area R1 and a second portioncorresponding to the second active area R2. A second contact C2 isprovided in the first portion of the third gate pattern GP3. The secondcontact C2 may extend in a direction perpendicular to the first andsecond active areas R1 and R2, and may be connected with a wiring overthe first and second active areas R1 and R2. The second contact C2 maysupply the first clock signal n to the first portion of the third gatepattern GP3.

A third contact C3 is provided in the second portion of the third gatepattern GP3. The third contact C3 may extend in a directionperpendicular to the first and second active areas R1 and R2, and may beconnected with a wiring over the first and second active areas R1 andR2. The third contact C3 may supply the second clock signal b to thesecond portion of the third gate pattern GP3.

In the first active area R1, a fourth contact C4 may be provided betweenthe third and fourth gate patterns GP3 and GP4. In the second activearea R2, a fifth contact C5 may be provided between the third and fourthgate patterns GP3 and GP4. The fourth and fifth contacts C4 and C5 mayextend in a direction perpendicular to the first and second active areasR1 and R2, and may be connected in common over the first and secondactive areas R1 and R2. Since the fourth and fifth contacts C4 and C5are connected in common to each other, the 3_1st to 3_4th transistors151 to 154 may be connected in series between the first power contactPC1 supplied with the power supply voltage VDD and the first groundcontact GC1 supplied with the ground voltage VSS. The fourth and fifthcontacts C4 and C5 may be electrically connected with inputs of thefourth and sixth inverters 160 and 180.

In the first active area R1, the fifth gate pattern GP5 may form the5_1st transistor 171 together with portions of the first active area R1which are adjacent to the fifth gate pattern GP5. In the first activearea R1, the fourth gate pattern GP4 may form the 5_2nd transistor 172together with portions of the first active area R1 which are adjacent tothe fourth gate pattern GP4. The 5_1st and 5_2nd transistors 171 and 172may be connected in series to each other.

In the second active area R2, the fifth gate pattern GP5 may form the5_4th transistor 174 together with portions of the second active areaR2, which are adjacent to the fifth gate pattern GP5. In the secondactive area R2, the fourth gate pattern GP4 may form the 5_3rdtransistor 173 together with portions of the second active area R2 whichare adjacent to the fourth gate pattern GP4. The 5_3rd and 5_4thtransistors 173 and 174 may be connected in series to each other.

An eighth contact C8 may be provided in the fifth gate pattern GP5 ofthe 5_1st and 5_4th transistors 171 and 174. The eighth contact C8 mayextend in a direction perpendicular to the first and second active areasR1 and R2, and may be connected with a wiring over the first and secondactive areas R1 and R2. The eighth contact C8 may be electricallyconnected with an input of the fifth inverter 170.

The fourth gate pattern GP4 may be divided into a first portioncorresponding to the first active area R1 and a second portioncorresponding to the second active area R2. A sixth contact C6 isprovided in the first portion of the fourth gate pattern GP4. The sixthcontact C6 may extend in a direction perpendicular to the first andsecond active areas R1 and R2, and may be connected with a wiring overthe first and second active areas R1 and R2. The sixth contact C6 maysupply the second clock signal b to the first portion of the fourth gatepattern GP4.

A seventh contact C7 is provided in the second portion of the fourthgate pattern GP4. The seventh contact C7 may extend in a directionperpendicular to the first and second active areas R1 and R2, and may beconnected with a wiring over the first and second active areas R1 andR2. The seventh contact C7 may supply the first clock signal n to thesecond portion of the fourth gate pattern GP4.

Since the fourth and fifth contacts C4 and C5 are connected in common toeach other, the 5_1st to 5_4th transistors 171 to 174 may be connectedin series between the second power contact PC2 supplied with the powersupply voltage VDD and the second ground contact GC2 supplied with theground voltage VSS.

According to the layout of FIG. 3, the third inverter 150 and the fifthinverter 170 are implemented with the transistors 151, 152, 171 and 172which are formed between the first power contact PC1 and the secondpower contact PC2 supplied with the power supply voltage VDD over thefirst and second fins FIN1 and FIN2 forming the first active area R1 ofthe P-type, and the transistors 153, 154, 173 and 174 which are formedbetween the first ground contact GC1 and the second ground contact GC2supplied with the ground voltage VSS over the third and fourth fins FIN3and FIN4 forming the second active area R2 of the N-type.

The first and second power contacts PC1 and PC2 and the first and secondground contacts GC1 and GC2 may be disposed around the layout of thethird and fifth inverters 150 and 170. Accordingly, the power supplyvoltage VDD and the ground voltage VSS are supplied to the first gatepattern GP1 and the sixth gate pattern GP6 through the first and secondpower contacts PC1 and PC2 and the first and second ground contacts GC1and GC2. That is, any other element that needs the power supply voltageVDD or the ground voltage VSS may be disposed to share the power supplyvoltage VDD and the ground voltage VSS supplied through the first powercontacts PC1 and PC2 and the first and second ground contacts GC1 andGC2 with the third and fifth inverters 150 and 170. Accordingly, thelayout efficiency of the flip-flop including the third and fifthinverters 150 and 170 may increase, and the size of the flip-flop 100may decrease.

FIG. 4 illustrates an example in which the fourth inverter 160 sharesthe power supply voltage VDD and the ground voltage VSS of the third andfifth inverters 150 and 170 of FIG. 3. In FIG. 4, configurationsassociated with the 3_1st to 3_4th transistors 151 to 154 and the 5_1stto 5_4th transistors 171 to 174 are the same as illustrated in FIG. 3,and a description thereof is thus omitted. Compared with FIG. 3, aseventh gate pattern GP7 is added in FIG. 4.

Referring to FIGS. 1 and 4, the sixth gate pattern GP6 may form the4_1st transistor 161 together with portions of the first active area R1which are adjacent to the sixth gate pattern GP6. The sixth gate patternGP6 may form the 4_2nd transistor 162 together with portions of thesecond active area R2 which are adjacent to the sixth gate pattern GP6.A ninth contact C9 may be provided in the sixth gate pattern GP6 of the4_1st and 4_2nd transistors 161 and 162. The ninth contact C9 may extendin a direction perpendicular to the first and second active areas R1 andR2, and may be connected with a wiring over the first and second activeareas R1 and R2. The ninth contact C9 may be electrically connected withan input of the fourth inverter 160. The ninth contact C9 may beelectrically connected with the fourth and fifth contacts C4 and C5 thatcorrespond to an output of the third inverter 150.

In the first active area R1, a tenth contact C10 may be provided betweenthe sixth and seventh gate patterns GP6 and GP7. In the second activearea R2, an eleventh contact C11 may be provided between the sixth andseventh gate patterns GP6 and GP7. The tenth and eleventh contacts C10and C11 may extend in a direction perpendicular to the first and secondactive areas R1 and R2, and may be connected in common over the firstand second active areas R1 and R2. Since the tenth and eleventh contactsC10 and C11 are connected in common to each other, the 4_1st and 4_2ndtransistors 161 and 162 may be connected in series between the secondpower contact PC2 supplied with the power supply voltage VDD and thesecond ground contact GC2 supplied with the ground voltage VSS. Thetenth and eleventh contacts C10 and C11 may correspond to an output ofthe fourth inverter 160. The tenth and eleventh contacts C10 and C11 maybe electrically connected with the eighth contact C8.

As illustrated in FIG. 4, the fourth inverter 160 may be disposed toshare the second power contact PC2 supplied with the power supplyvoltage VDD and the second ground contact GC2 supplied with the groundvoltage VSS with the fifth inverter 170. According to theabove-described layout, power contacts and ground contacts to bedisposed upon implementing the flip-flop 100 decrease in number.Accordingly, the size of the flip-flop 100 is reduced.

In an example embodiment, the fourth inverter 160 is illustrated in FIG.4 as sharing the power supply voltage VDD and the ground voltage VSSwith the fifth inverter 170. However, the fourth inverter 160 may bedisposed to share the power supply voltage VDD and the ground voltageVSS with the third inverter 150. For example, the first gate pattern GP1may be used as gates of the 4_1st and 4_2nd transistors 161 and 162. Theninth contact C9 may be disposed on the first gate pattern GP1. Thetenth and eleventh contacts C10 and C11 may be disposed on left side ofthe first gate pattern GP1.

In an example embodiment, the fourth inverter 160 is illustrated in FIG.4 as sharing the power supply voltage VDD and the ground voltage VSSwith the fifth inverter 170. However, instead of the fourth inverter160, the sixth inverter 180 may share the power supply voltage VDD andthe ground voltage VSS with the fifth inverter 170. For example, thesixth gate pattern GP6 may form the 6_1st transistor 181 together withportions of the first active area R1 which are adjacent to the sixthgate pattern GP6, and may form the 6_2nd transistor 182 together withportions of the second active area R2 which are adjacent to the sixthgate pattern GP6.

In an example embodiment, the fourth inverter 160 may be disposed toshare the power supply voltage VDD and the ground voltage VSS with thefifth inverter 170 or the third inverter 150, and the sixth inverter 180may be disposed to share the power supply voltage VDD and the groundvoltage VSS with the third inverter 150 or the fifth inverter 170.

FIG. 5 illustrates an application example of arrangement of the thirdand fifth inverters 150 and 170. The third and fourth gate patterns GP3and GP4 of FIG. 3 may be replaced with the third to fifth gate patternsGP3 to GP5 of FIG. 4. The fifth and sixth gate patterns GP5 and GP6 ofFIG. 3 may correspond to the sixth and seventh gate patterns GP6 and GP7of FIG. 5.

Referring to FIGS. 1 and 5, each of the third to fifth gate patterns GP3to GP5 may be divided into a first portion corresponding to the firstactive area R1 and a second portion corresponding to the second activearea R2.

The third gate pattern GP3 may form the 3_2nd transistor 152 togetherwith portions of the first active area R1 which are adjacent to thethird gate pattern GP3. The second portion of the third gate pattern GP3may be ignored by a first jumper J1. The first jumper J1 mayelectrically connect portions of the second active area R2 which areseparated by the second portion of the third gate pattern GP3.

The first portion of the fourth gate pattern GP4 may form the 5_2ndtransistor 172 together with portions of the first active area R1 whichare adjacent to the first portion of the fourth gate pattern GP4. Thesecond portion of the fourth gate pattern GP4 may form the 3_3rdtransistor 153 together with portions of the second active area R2 whichare adjacent to the second portion of the fourth gate pattern GP4.

The first portion of the fifth gate pattern GP5 may be ignored by asecond jumper J2. The second jumper J2 may electrically connect portionsof the first active area R1 which are separated by the first portion ofthe fifth gate pattern GP5. The second portion of the fifth gate patternGP5 may form the 5_3rd transistor 173 together with portions of thesecond active area R2 which are adjacent to the second portion of thefifth gate pattern GP5.

FIG. 6 illustrates an example in which the power supply voltage VDD andthe ground voltage VSS of the third and fifth inverters 150 and 170 ofFIG. 5 are shared. In an example embodiment, the fourth inverter 160 orthe sixth inverter 180 may share the power supply voltage VDD and theground voltage VSS with the third and fifth inverters 150 and 170.

The arrangement of the 3_1st to 3_4th transistors 151 to 154 and the5_1st to 5_4th transistors 171 to 174 may be the same as illustrated inFIG. 5. Compared with FIG. 5, an eighth gate pattern GP8 is added inFIG. 6.

The seventh gate pattern GP7 may correspond to the sixth gate patternGP6 of FIG. 4. For example, the seventh gate pattern GP7 may form the4_1st transistor 161 together with portions of the first active area R1which are adjacent to the seventh gate pattern GP7, and may form the4_2nd transistor 162 together with portions of the second active area R2which are adjacent to the seventh gate pattern GP7.

The fourth inverter 160 illustrated in FIG. 6 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 160 or the sixthinverter 180 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 150 or the fifth inverter170.

FIG. 7 illustrates an application example of the third and fifthinverters 150 and 170 of FIG. 5. Compared with FIG. 5, the fourth gatepattern GP4 of FIG. 7 may not be separated into a first portion and asecond portion. The fourth gate pattern GP4 may form the 5_2ndtransistor 172 together with portions of the first active area R1 whichare adjacent to the fourth gate pattern GP4, and may form the 3_3rdtransistor 153 together with portions of the second active area R2 whichare adjacent to the fourth gate pattern GP4.

In FIG. 5, the sixth contact C6 disposed in the first portion of thefourth gate GP4 supplies the second clock signal b, and the thirdcontact C3 disposed in the second portion of the fourth gate pattern GP4supplies the second clock signal b. Since the third and sixth contactsC3 and C6 transfer the same signal, one of the third and sixth contactsC3 and C6 may be removed without separating the fourth gate pattern GP4.

FIG. 8 illustrates an example in which the power supply voltage VDD andthe ground voltage VSS of the third and fifth inverters 150 and 170 ofFIG. 7 are shared. In an example embodiment, the fourth inverter 160 orthe sixth inverter 180 may share the power supply voltage VDD and theground voltage VSS with the third and fifth inverter 150 and 170.

The arrangement of the 3_1st to 3_4th transistors 151 to 154 and the5_1st to 5_4th transistors 171 to 174 may be the same as illustrated inFIG. 7. Compared with FIG. 7, the eighth gate pattern GP8 is added inFIG. 8.

The seventh gate pattern GP7 may correspond to the sixth gate patternGP6 of FIG. 4. For example, the seventh gate pattern GP7 may form the4_1st transistor 161 together with portions of the first active area R1which are adjacent to the seventh gate pattern GP7, and may form the4_2nd transistor 162 together with portions of the second active area R2which are adjacent to the seventh gate pattern GP7.

The fourth inverter 160 illustrated in FIG. 8 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 160 or the sixthinverter 180 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 150 or the fifth inverter170.

FIG. 9 illustrates an application example of the flip-flop 100 ofFIG. 1. Referring to FIG. 9, a flip-flop 200 includes an input interface210 and first to sixth inverters 230 to 280.

The first to sixth inverters 230 to 280 are the same as the first tosixth inverters 130 to 180 described with reference to FIG. 1, and adescription thereof is thus omitted.

The input interface 210 inverts an input signal D in synchronizationwith the first and second clock signals n and b, and transfers theinverted input signal to the first inverter 130. The input interface 210includes first to fourth input transistors 211 to 214. The first tofourth input transistors 211 to 214 are connected in series between thepower node and the ground node. The first and second input transistors211 and 212 may be P-type transistors, and the third and fourth inputtransistors 213 and 214 may be N-type transistors.

The input signal D is transferred to gates of the first and fourth inputtransistors 211 and 214. The second clock signal b is transferred to agate of the second input transistor 212. The first clock signal n istransferred to a gate of the third input transistor 213. The inputinterface 210 may be implemented with a 3-state inverter that operatesin synchronization with the first and second clock signals n and b. Anode between the second and third input transistors 212 and 213 may bean output of the input interface 210. The output of the input interface210 is connected to an input of the first inverter 230.

In FIG. 9, the input interface 210 and the second inverter 240 have thesame structure and connection as the third and fifth inverters 250 and270 except for the first and second clock signals n and b. Accordingly,through mutual exchange of contacts for transferring the first andsecond clock signals n and b, the input interface 210 and the secondinverter 240 may be implemented as illustrated in FIG. 3, 5 or 7. Also,as illustrated in FIG. 4, 6 or 8, the first inverter 230 may share thepower supply voltage VDD and the ground voltage VSS with the inputinterface 210 and the second inverter 240.

If the input interface 210 and the second inverter 240 are implementedas illustrated in FIG. 3, 5 or 7, and the third and fifth inverters 250and 270 are implemented as illustrated in FIG. 3, 5 or 7, the layoutefficiency of the flip-flop 200 may be further improved, and the size ofthe flip-flop 200 may be further reduced.

FIG. 10 illustrates an application example of the flip-flop 200 of FIG.9. Referring to FIG. 10, a flip-flop 300 includes an input interface 310and first to sixth inverters 330 to 380.

The input interface 310 and the second, third, fifth and sixth inverters340, 350, 370 and 380 are configured the same as the input interface 210and the second, third, fifth and sixth inverters 240, 250, 270 and 280of FIG. 9, and a description thereof is thus omitted.

The first inverter 330 includes 1_1st to 1_4th transistors 331 to 334.The 1_1st and 1_3rd transistors 331 and 333 are connected in seriesbetween the power node supplied with the power supply voltage VDD andthe 1_4th transistor 334. The 1_1st and 1_3rd transistors 331 and 333may be of a P-type. The 1_2nd and 1_4th transistors 332 and 334 areconnected in parallel between the ground node supplied with the groundvoltage VSS and the 1_3rd transistor 333. The 1_2nd and 1_4thtransistors 332 and 334 may be of an N-type.

An output of the input interface 310 is transferred to gates of the1_1st and 1_3rd transistors 331 and 332. A reset signal “R” istransferred to gates of the 1_3rd and 1_4th transistors 333 and 334. Ifthe reset signal “R” is activated, that is, if the reset signal “R” hasthe power supply voltage VDD or a voltage similar in level to the powersupply voltage VDD, a node between the 1_3rd and 1_4th transistors 333and 334 may be reset with the ground voltage VSS. If the reset signal“R” is deactivated, that is, if the reset signal “R” has the groundvoltage VSS or a voltage similar in level to the ground voltage VSS, the1_3rd transistor 333 may maintain a turn-on state. The 1_1st and 1_2ndtransistors 331 and 332 may operate as an inverter.

The fourth inverter 360 includes 4_1st to 4_4th transistors 361 to 364.The 4_1st and 4_3rd transistors 361 and 363 are connected in seriesbetween the power node supplied with the power supply voltage VDD andthe 4_4th transistor 364. The 4_1st and 4_3rd transistors 361 and 363may be of a P-type. The 4_2nd and 4_4th transistors 362 and 364 areconnected in parallel between the ground node supplied with the groundvoltage VSS and the 4_3rd transistor 363. The 4_2nd and 4_4thtransistors 362 and 364 may be of an N-type.

An output of the third inverter 350 is transferred to gates of the 4_1stand 4_2nd transistors 361 and 362. The reset signal “R” is transferredto gates of the 4_3rd and 4_4th transistors 363 and 364. If the resetsignal “R” is activated, a node between the 4_3rd and 4_4th transistors363 and 364 may be reset with the ground voltage VSS. If the resetsignal “R” is deactivated, the 4_3rd transistor 363 may maintain aturn-on state. The 4_1st and 4_2nd transistors 361 and 362 may operateas an inverter.

FIG. 11 illustrates an example in which the fourth inverter 360 of FIG.10 shares the power supply voltage VDD and the ground voltage VSS withthe third and fifth inverters 350 and 370. Referring to FIGS. 3 and 11,the arrangement of the 3_1st to 3_4th transistors 351 to 354 and the5_1st to 5_4th transistors 371 to 374 is the same as the arrangement ofthe 3_1st to 3_4th transistors 151 to 154 and the 5_1st to 5_4thtransistors 171 to 174, and a description thereof is thus omitted.

Compared with FIG. 3, the seventh and eighth gate patterns GP7 and GP8are added in FIG. 11. The sixth gate pattern GP6 may form the 4_1sttransistor 361 together with portions of the first active area R1 whichare adjacent to the sixth gate pattern GP6, and may form the 4_2ndtransistor 362 together with portions of the second active area R2 whichare adjacent to the sixth gate pattern GP6. The 4_1st transistor 361 mayreceive the power supply voltage VDD from the second power contact PC2.The 4_2nd transistor 362 may receive the ground voltage VSS from thesecond ground contact GC2.

A ninth contact C9 may be provided in the sixth gate pattern GP6 of the4_1st and 4_2nd transistors 361 and 362. The ninth contact C9 may extendin a direction perpendicular to the first and second active areas R1 andR2, and may be connected with a wiring over the first and second activeareas R1 and R2. The ninth contact C9 may correspond to an input of thefourth inverter 360.

The seventh gate pattern GP7 may form the 4_3rd transistor 363 togetherwith portions of the first active area R1 which are adjacent to theseventh gate pattern GP7, and may form the 4_4th transistor 364 togetherwith portions of the second active area R2 which are adjacent to theseventh gate pattern GP7. The eleventh contact C11 may be provided inthe seventh gate pattern GP7 of the 4_3rd and 4_4th transistors 363 and364. The eleventh contact C11 may extend in a direction perpendicular tothe first and second active areas R1 and R2, and may be connected with awiring over the first and second active areas R1 and R2. The eleventhcontact C11 may transfer the reset signal “R” to the 4_3rd and 4_4thtransistors 363 and 364.

In the second active area R2, a third contact GC3 may be providedbetween the seventh and eighth gate patterns GP7 and GP8. The thirdcontact GC3 may extend in a direction perpendicular to the first andsecond active areas R1 and R2, and may be connected with a wiring overthe first and second active areas R1 and R2. The 4_2nd transistor 364may receive the ground voltage VSS from the third ground contact GC3.

In the second active area R2, the tenth contact C10 may be providedbetween the sixth and seventh gate patterns GP6 and GP7. In the firstactive area R1, a twelfth contact C12 may be provided between theseventh and eighth gate patterns GP7 and GP8. The tenth and twelfthcontacts C10 and C12 may extend in a direction perpendicular to thefirst and second active areas R1 and R2, and may be connected in commonover the first and second active areas R1 and R2. The tenth and twelfthcontacts C10 and C12 may correspond to an output of the fourth inverter360.

The fourth inverter 360 illustrated in FIG. 11 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 360 or the sixthinverter 380 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 350 or the fifth inverter370.

The input interface 310 and the first and second inverters 330 and 340may be also implemented as illustrated in FIG. 11. For example, thesixth gate pattern GP6 may form the 1_1st transistor 331 together withportions of the first active area R1 which are adjacent to the sixthgate pattern GP6, and may form the 1_2nd transistor 332 together withportions of the second active area R2 which are adjacent to the sixthgate pattern GP6. The ninth contact C9 may transfer the input signal D.The seventh gate pattern GP7 may form the 1_3rd transistor 333 togetherwith portions of the first active area R1 which are adjacent to theseventh gate pattern GP7, and may form the 1_4th transistor 334 togetherwith portions of the second active area R2 which are adjacent to theseventh gate pattern GP7. The eleventh contact C11 may transfer thereset signal “R”. Portions that are not set forth above may beconfigured the same as described with reference to the third to fifthinverters 350 to 370.

FIG. 12 illustrates an application example of arrangement of the thirdto fifth inverters 350 to 370 of FIG. 11. Referring to FIG. 12, thearrangement of the 3_1st to 3_4th transistors 351 to 354 and the 5_1stto 5_4th transistors 371 to 374 may be the same as illustrated in FIG.5. Compared with FIG. 5, the eighth and ninth gate patterns GP8 and GP9are added in FIG. 12.

The seventh to ninth gate patterns GP7 to GP9 may correspond to thesixth to eighth gate patterns GP6 to GP8 of FIG. 11, respectively. Forexample, the seventh gate pattern GP7 may be used to form the 4_1st and4_2nd transistors 361 and 362. The eighth gate pattern GP8 may be usedto form the 4_3rd and 4_4th transistors 363 and 364.

The fourth inverter 360 illustrated in FIG. 12 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 360 or the sixthinverter 380 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 350 or the fifth inverter370.

The input interface 310 and the first and second inverters 330 and 340may be also implemented as illustrated in FIG. 12. For example, theseventh gate pattern GP7 may form the 1_1st transistor 331 together withportions of the first active area R1 which are adjacent to the seventhgate pattern GP7, and may form the 1_2nd transistor 332 together withportions of the second active area R2 which are adjacent to the seventhgate pattern GP7. The ninth contact C9 may transfer the input signal D.The eighth gate pattern GP8 may form the 1_3rd transistor 333 togetherwith portions of the first active area R1 which are adjacent to theeighth gate pattern GP8, and may form the 1_4th transistor 334 togetherwith portions of the second active area R2 which are adjacent to theeighth gate pattern GP8. The eleventh contact C11 may transfer the resetsignal “R”. Portions that are not set forth above may be configured thesame as described with reference to the third to fifth inverters 350 to370.

FIG. 13 illustrates another application example of arrangement of thethird to fifth inverters 350 to 370 of FIG. 11. Referring to FIG. 13,the arrangement of the 3_1st to 3_4th transistors 351 to 354 and the5_1st to 5_4th transistors 371 to 374 may be the same as illustrated inFIG. 7. Compared with FIG. 7, the eighth and ninth gate patterns GP8 andGP9 are added in FIG. 13.

The seventh to ninth gate patterns GP7 to GP9 may correspond to thesixth to eighth gate patterns GP6 to GP8 of FIG. 11, respectively. Forexample, the seventh gate pattern GP7 may be used to form the 4_1st and4_2nd transistors 361 and 362. The eighth gate pattern GP8 may be usedto form the 4_3rd and 4_4th transistors 363 and 364.

The fourth inverter 360 illustrated in FIG. 13 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 360 or the sixthinverter 380 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 350 or the fifth inverter370.

The input interface 310 and the first and second inverters 330 and 340may be also implemented as illustrated in FIG. 13.

FIG. 14 illustrates another application example of the flip-flop 200 ofFIG. 9. Referring to FIG. 14, a flip-flop 400 includes an inputinterface 410 and first to sixth inverters 430 to 480.

The input interface 410 and the second, third, fifth and sixth inverters440, 450, 470, and 480 are configured the same as the input interface210 and the second, third, fifth and sixth inverters 240, 250, 270 and280 of FIG. 9, and a description thereof is thus omitted.

The first inverter 430 includes 1_1st to 1_4th transistors 331 to 334.The 1_1st and 1_3rd transistors 431 and 433 are connected in parallelbetween the power node supplied with the power supply voltage VDD andthe 1_4th transistor 434. The 1_1st and 1_3rd transistors 431 and 433may be of a P-type. The 1_2nd and 1_4th transistors 432 and 434 areconnected in series between the ground node supplied with the groundvoltage VSS and the 1_3rd transistor 433. The 1_2nd and 1_4thtransistors 432 and 434 may be of an N-type.

An output of the input interface 410 is transferred to gates of the1_1st and 1_2nd transistors 431 and 432. A set signal “S” is transferredto gates of the 1_3rd and 1_4th transistors 433 and 434. If the setsignal “S” is activated, that is, if the set signal “S” has the groundvoltage VSS or a voltage similar in level to the ground voltage VSS, anode between the 1_3rd and 1_4th transistors 433 and 434 may be set withthe power supply voltage VDD. If the set signal “S” is deactivated, thatis, if the set signal “S” has the power supply voltage VDD or a voltagesimilar in level to the power supply voltage VDD, the 1_4th transistor434 may maintain a turn-on state. The 1_1st and 1_2nd transistors 431and 432 may operate as an inverter.

The fourth inverter 460 includes 4_1st to 4_4th transistors 461 to 464.The 4_1st and 4_3rd transistors 461 and 463 are connected in parallelbetween the power node supplied with the power supply voltage VDD andthe 4_2nd transistor 462. The 4_1st and 4_3rd transistors 461 and 463may be of a P-type. The 4_2nd and 4_4th transistors 462 and 464 areconnected in series between the ground node supplied with the groundvoltage VSS and the 4_3rd transistor 463. The 4_2nd and 4_4thtransistors 462 and 464 may be of an N-type.

An output of the third inverter 450 is transferred to gates of the 4_1stand 4_2nd transistors 461 and 462. The set signal “S” is transferred togates of the 4_3rd and 4_4th transistors 463 and 464. If the set signal“S” is activated, a node between the 4_2nd and 4_3rd transistors 462 and463 may be set with the power supply voltage VDD. If the set signal “S”is deactivated, the 4_4th transistor 464 may maintain a turn-on state.The 4_1st and 4_2nd transistors 461 and 462 may operate as an inverter.

FIG. 15 illustrates an example in which the fourth inverter 460 of FIG.14 shares the power supply voltage VDD and the ground voltage VSS withthe third and fifth inverters 450 and 470. Referring to FIGS. 3 and 11,the arrangement of the 3_1st to 3_4th transistors 451 to 454 and the5_1st to 5_4th transistors 471 to 474 is the same as the arrangement ofthe 3_1st to 3_4th transistors 151 to 154 and the 5_1st to 5_4thtransistors 171 to 174, and a description thereof is thus omitted.

Compared with FIG. 3, the seventh and eighth gate patterns GP7 and GP8are added in FIG. 11. The sixth gate pattern GP6 may form the 4_3rdtransistor 463 together with portions of the first active area R1 whichare adjacent to the sixth gate pattern GP6, and may form the 4_4thtransistor 464 together with portions of the second active area R2 whichare adjacent to the sixth gate pattern GP6. The 4_3rd transistor 463 mayreceive the power supply voltage VDD from the second power contact PC2.The 4_4th transistor 464 may receive the ground voltage VSS from thesecond ground contact GC2.

The ninth contact C9 may be provided in the sixth gate pattern GP6 ofthe 4_3rd and 4_4th transistors 463 and 464. The ninth contact C9 mayextend in a direction perpendicular to the first and second active areasR1 and R2, and may be connected with a wiring over the first and secondactive areas R1 and R2. The ninth contact C9 may transfer the set signal“S” to the 4_3rd and 4_4th transistors 463 and 464.

The seventh gate pattern GP7 may form the 4_1st transistor 461 togetherwith portions of the first active area R1 which are adjacent to theseventh gate pattern GP7, and may form the 4_2nd transistor 462 togetherwith portions of the second active area R2 which are adjacent to theseventh gate pattern GP7. The eleventh contact C11 may be provided inthe seventh gate pattern GP7 of the 4_1st and 4_2nd transistors 461 and462. The eleventh contact C11 may extend in a direction perpendicular tothe first and second active areas R1 and R2, and may be connected with awiring over the first and second active areas R1 and R2. The eleventhcontact C11 may correspond to an input of the fourth inverter 460.

In the first active area R1, the third power contact PC3 may be disposedbetween the seventh and eighth gate patterns GP7 and GP8. The thirdpower contact PC3 may extend in a direction perpendicular to the firstand second active areas R1 and R2, and may be connected with a wiringover the first and second active areas R1 and R2. The 4_1st transistor461 may receive the power supply voltage VDD from the third powercontact PC3.

In the first active area R1, the tenth contact C10 may be providedbetween the sixth and seventh gate patterns GP6 and GP7. In the secondactive area R2, the twelfth contact C12 may be provided between theseventh and eighth gate patterns GP7 and GP8. The tenth and twelfthcontacts C10 and C12 may extend in a direction perpendicular to thefirst and second active areas R1 and R2, and may be connected in commonover the first and second active areas R1 and R2. The tenth and twelfthcontacts C10 and C12 may correspond to an output of the fourth inverter460.

The fourth inverter 460 illustrated in FIG. 15 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 460 or the sixthinverter 480 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 450 or the fifth inverter470.

The input interface 410 and the first and second inverters 430 and 440may be also implemented as illustrated in FIG. 15. For example, thesixth gate pattern GP6 may form the 1_3rd transistor 433 together withportions of the first active area R1 which are adjacent to the sixthgate pattern GP6, and may form the 1_4th transistor 434 together withportions of the second active area R2 which are adjacent to the sixthgate pattern GP6. The ninth contact C9 may transfer the set signal “S”.The seventh gate pattern GP7 may form the 1_1st transistor 431 togetherwith portions of the first active area R1 which are adjacent to theseventh gate pattern GP7, and may form the 1_2nd transistor 432 togetherwith portions of the second active area R2 which are adjacent to theseventh gate pattern GP7. The eleventh contact C11 may transfer theinput signal D. Portions that are not set forth above may be configuredthe same as described with reference to the third to fifth inverters 450to 470.

FIG. 16 illustrates an application example of arrangement of the thirdto fifth inverters 450 to 470 of FIG. 15. Referring to FIG. 16, thearrangement of the 3_1st to 3_4th transistors 451 to 454 and the 5_1stto 5_4th transistors 471 to 474 may be the same as illustrated in FIG.5. Compared with FIG. 5, the eighth and ninth gate patterns GP8 and GP9are added in FIG. 16.

The seventh to ninth gate patterns GP7 to GP9 may correspond to thesixth to eighth gate patterns GP6 to GP8 of FIG. 15, respectively. Forexample, the seventh gate pattern GP7 may be used to form the 4_3rd and4_4th transistors 463 and 464. The eighth gate pattern GP8 may be usedto form the 4_1st and 4_2nd transistors 461 and 462.

The fourth inverter 460 illustrated in FIG. 16 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 460 or the sixthinverter 480 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 450 or the fifth inverter470.

The input interface 410 and the first and second inverters 430 and 440may be also implemented as illustrated in FIG. 16. For example, theseventh gate pattern GP7 may form the 1_3rd transistor 433 together withportions of the first active area R1 which are adjacent to the seventhgate pattern GP7, and may form the 1_4th transistor 434 together withportions of the second active area R2 which are adjacent to the seventhgate pattern GP7. The ninth contact C9 may transfer the set signal “S”.The eighth gate pattern GP8 may form the 1_1st transistor 431 togetherwith portions of the first active area R1 which are adjacent to theeighth gate pattern GP8, and may form the 1_2nd transistor 432 togetherwith portions of the second active area R2 which are adjacent to theeighth gate pattern GP8. The eleventh contact C11 may transfer the inputsignal D.

FIG. 17 illustrates another application example of arrangement of thethird to fifth inverters 450 to 470 of FIG. 15. Referring to FIG. 17,the arrangement of the 3_1st to 3_4th transistors 451 to 454 and the5_1st to 5_4th transistors 471 to 474 may be the same as illustrated inFIG. 7. Compared with FIG. 7, the eighth and ninth gate patterns GP8 andGP9 are added in FIG. 17.

The seventh to ninth gate patterns GP7 to GP9 may correspond to thesixth to eighth gate patterns GP6 to GP8 of FIG. 15, respectively. Forexample, the seventh gate pattern GP7 may be used to form the 4_3rd and4_4th transistors 463 and 464. The eighth gate pattern GP8 may be usedto form the 4_1st and 4_2nd transistors 461 and 462.

The fourth inverter 460 illustrated in FIG. 17 is an example. Asdescribed with reference to FIG. 4, the fourth inverter 460 or the sixthinverter 480 may be disposed to share the power supply voltage VDD andthe ground voltage VSS with the third inverter 450 or the fifth inverter470.

The input interface 410 and the first and second inverters 430 and 440may be also implemented as illustrated in FIG. 17.

According to an example embodiment of the inventive concept, a 3-stateinverter is disposed between a master latch and a slave latch of aflip-flop. Since a taper is removed in a layout of the flip-flop, theflip-flop capable of preventing deterioration in a characteristic and adecrease in yield is provided. The 3-state inverter is disposed betweentwo power contacts and ground contacts together with one inverter of theslave latch. Since the power contacts and the ground contacts are sharedwith any other elements, the flip-flop having improved layout efficiencyis provided.

While the inventive concept has been described with reference to exampleembodiments, it will be apparent to those skilled in the art thatvarious changes and modifications may be made without departing from thespirit and scope of the inventive concept. Therefore, it should beunderstood that the above example embodiments are not limiting, butillustrative.

What is claimed is:
 1. A flip-flop comprising: an input interfaceconfigured to receive a first signal, and output the received firstsignal as a second signal in synchronization with a clock; a first latchcomprising a first inverter and a second inverter, and configured tostore the second signal output from the input interface insynchronization with the clock; a third inverter configured to outputthe second signal stored in the first latch as a third signal insynchronization with the clock; and a second latch comprising a fourthinverter and a fifth inverter, and configured to store the third signaloutput from the third inverter in synchronization with the clock,wherein the third inverter and the fifth inverter comprise: firsttransistors of a first type formed between a first power contact and asecond power contact supplied with a power supply voltage on first-typefins; and second transistors of a second type formed between a firstground contact and a second ground contact supplied with a groundvoltage on second-type fins.
 2. The flip-flop of claim 1, whereinanother power contact is not disposed between the first power contactand the second power contact on the first-type fins, and wherein anotherground contact is not disposed between the first ground contact and thesecond ground contact on the second-type fins.
 3. The flip-flop of claim1, wherein first, second, third, and fourth gates are disposed betweenthe first power contact and the second power contact on the first-typefins, wherein fifth, sixth, seventh, and eighth gates are disposedbetween the first ground contact and the second ground contact on thesecond-type fins, wherein the first gate is connected with the fifthgate, and wherein the fourth gate is connected with the eighth gate. 4.The flip-flop of claim 3, wherein an output of the first latch isconnected with the first gate, and wherein an output of the fourthinverter is connected with the fourth gate.
 5. The flip-flop of claim 3,wherein the clock comprises a first clock and a second clock, whereinthe first clock is supplied to the second gate and the seventh gate, andwherein the second clock is supplied to the third gate and the sixthgate.
 6. The flip-flop of claim 3, wherein a ninth gate is disposedadjacent to the second power contact and the second ground contact,wherein the second power contact is located between the fourth gate andthe ninth gate on the first-type fins, wherein the second ground contactis located between the eighth gate and the ninth gate on the second-typefins, and wherein the ninth gate forms the fourth inverter together withthe first-type fins and the second-type fins.
 7. The flip-flop of claim6, wherein a portion of the first-type fins, which is adjacent to theninth gate and opposite to the second power contact, and a portion ofthe second-type fins, which is adjacent to the ninth gate and oppositeto the second ground contact are connected with the eighth gate.
 8. Theflip-flop of claim 3, further comprising: a sixth inverter configured toinvert the third signal and output the inverted third signal as a fourthsignal, wherein a ninth gate is disposed adjacent to the second powercontact and the second ground contact, wherein the second power contactis located between the fourth gate and the ninth gate on the first-typefins, wherein the second ground contact is located between the eighthgate and the ninth gate on the second-type fins, and wherein the ninthgate forms the sixth inverter together with the first-type fins and thesecond-type fins.
 9. The flip-flop of claim 3, wherein ninth and tenthgates are disposed adjacent to the second power contact and the secondground contact, wherein the second power contact is located between thefourth gate and the ninth gate on the first-type fins, wherein thesecond ground contact is located between the eighth gate and the ninthgate on the second-type fins, wherein a reset signal is supplied to thetenth gate, wherein an output of the third inverter is supplied to theninth gate, wherein the first-type fins of a side of the tenth gate areconnected with the eighth gate, wherein a third ground contact suppliedwith a ground voltage is disposed on the second-type fins of the side ofthe tenth gate, and wherein the second-type fins between the ninth gateand the tenth gate are connected with the eighth gate.
 10. The flip-flopof claim 3, wherein ninth and tenth gates are disposed adjacent to thesecond power contact and the second ground contact, wherein the secondpower contact is located between the fourth gate and the ninth gate onthe first-type fins, wherein the second ground contact is locatedbetween the eighth gate and the ninth gate on the second-type fins,wherein a set signal is supplied to the ninth gate, wherein an output ofthe third inverter is supplied to the tenth gate, wherein a third powercontact supplied with a power supply voltage is disposed on thefirst-type fins of a side of the tenth gate, wherein the second-typefins of the side of the tenth gate are connected with the eighth gate,and wherein the first-type fins between the ninth gate and the tenthgate are connected with the eighth gate.
 11. The flip-flop of claim 1,wherein first, second, third, fourth, and fifth gates are disposedbetween the first power contact and the second power contact, whereinsixth, seventh, eighth, ninth, and tenth gates are disposed between thefirst ground contact and the second ground contact, wherein the firstgate is connected with the sixth gate, wherein the fifth gate isconnected with the tenth gate, wherein an output of the first latch isconnected with the first gate, wherein an output of the fourth inverteris connected with the fifth gate, wherein the clock comprises a firstclock and a second clock, wherein the first clock is supplied to thesecond gate and the ninth gate, and wherein the second clock is suppliedto the third gate and the eighth gate.
 12. The flip-flop of claim 11,wherein a first jumper, which electrically connects the first-type finsseparated by the fourth gate, is disposed over the fourth gate, andwherein a second jumper, which electrically connects the second-typefins separated by the seventh gate, is disposed over the seventh gates.13. The flip-flop of claim 11, wherein the third gate and the ninth gateare connected to each other.
 14. The flip-flop of claim 1, wherein apower supply voltage of at least one of the first power contact and thesecond power contact and a ground voltage of at least one of the firstground contact and the second ground contact are shared with anotherelement.
 15. The flip-flop of claim 1, wherein the input interfacecomprises a sixth inverter configured to output the second signal insynchronization with the clock, wherein the second inverter and thesixth inverter comprise: third transistors of the first type formedbetween a third power contact and a fourth power contact supplied withthe power supply voltage on the first-type fins; and fourth transistorsof the second type formed between a third ground contact and a fourthground contact supplied with the ground voltage on the second-type fins.16. The flip-flop of claim 15, wherein first, second, third, and fourthgates are disposed between the third power contact and the fourth powercontact on the first-type fins, wherein fifth, sixth, seventh, andeighth gates are disposed between the third ground contact and thefourth ground contact on the second-type fins, wherein the first gate isconnected with the fifth gate, and wherein the fourth gate is connectedwith the eighth gate.
 17. The flip-flop of claim 16, wherein ninth andtenth gates are disposed adjacent to the fourth power contact and thefourth ground contact, wherein the fourth power contact is locatedbetween the fourth gate and the ninth gate on the first-type fins,wherein the fourth ground contact is located between the eighth gate andthe ninth gate on the second-type fins, wherein an output of the thirdinverter is supplied to the ninth gate, wherein a reset signal issupplied to the tenth gate, wherein the first-type fins of a side of thetenth gate are connected with the eighth gate, wherein a fifth groundcontact supplied with the ground voltage is disposed on the second-typefins of the side of the tenth gate, and wherein the second-type finsbetween the ninth gate and the tenth gate are connected with the eighthgate.
 18. The flip-flop of claim 16, wherein ninth and tenth gates aredisposed adjacent to the fourth power contact and the fourth groundcontact, wherein the fourth power contact is located between the fourthgate and the ninth gate on the first-type fins, wherein the fourthground contact is located between the eighth gate and the ninth gate onthe second-type fins, wherein an output of the third inverter issupplied to the tenth gate, wherein a set signal is supplied to theninth gate, wherein a fifth power contact supplied with the power supplyvoltage is disposed on the first-type fins of a side of the tenth gate,wherein the second-type fins of the side of the tenth gate are connectedwith the eighth gate, and wherein the first-type fins between the ninthgate and the tenth gate are connected with the eighth gate.
 19. Aflip-flop of claim 1 further comprising: a sixth inverter configured toinvert and output a signal output from a node between the third inverterand the second latch, wherein a power supply voltage of at least one ofthe first power contact and the second power contact and a groundvoltage of at least one of the first ground contact and the secondground contact are shared with one of the fourth inverter and the sixthinverter.
 20. A flip-flop comprising: an input interface configured toreceive a first signal, and output the received first signal as a secondsignal in synchronization with a clock; a first latch comprising a firstinverter and a second inverter, and configured to store the secondsignal output from the input interface in synchronization with theclock; a third inverter configured to output the second signal stored inthe first inverter as a third signal in synchronization with the clock;a second latch comprising a fourth inverter and a fifth inverter, andconfigured to store the third signal output from the third inverter insynchronization with the clock; and a sixth inverter configured toinvert the third signal and output the inverted third signal as a fourthsignal, wherein the third inverter includes first and second P-typemetal-oxide-semiconductor (PMOS) transistors and first and second N-typemetal-oxide-semiconductor (NMOS) transistors, wherein the fifth inverterincludes third and fourth PMOS transistors and third and fourth NMOStransistors, wherein the first to fourth PMOS transistors are disposedbetween a first power contact and a second power contact supplied with apower supply voltage on first-type fins; and wherein the first to fourthNMOS transistors are disposed between a first ground contact and asecond ground contact supplied with a ground voltage on second-typefins.